How Caching Works?

Member

I've seen that XenForo uses heavy caching and that's the reason behind it's so fast.

But, I would like to ask how XenForo invalidates a thread-listing page or post page cache so that users see latest information in ftont-end. I've seen that there's cache_lifetime => 10800 in config.php, so does this time is considered to invalidate a cache?